Only some of the options are being discussed here. See jam -h for a full listing of available options.

-q

Typically jam will attempt to build all targets, even if an error is encountered. '-q' instructs jam to quit immediately upon encountering an error. This is preferred, as it helps to find the actual cause for build failure.

-j#

Where # represents the number of threads to use. This is useful when building on SMP or multi-core machines.

Jam suffers from a bug that might make your build fail when using this option.

-a

Build all targets, even if they are current. Normally, this is not necessary.
You may need to do this once in a while because some of the jam rules are not perfect and does not set the dependencies between files properly. The most frequent case is when we update our copy of Freetype : this will prevent anyone to build without the -a switch.
You can also use this switch if something does not seem to get updated after some change you made. This is the case when you modify a jamfile : Jam does not check for that and will not rebuild things that should be affected by the changes.

-sx=y

Set variable x=y, overriding environment. One example is :

jam -sHAIKU_IGNORE_USER_BUILD_CONFIG=1 -q @release-raw

This will ensure that the release-* targets are built to the exact specifications of Haiku's DefaultBuildProfiles.

-dX

Enables debug output, where X can be one of the following:

(a)actions

(c)causes

(d)dependencies

(m)make tree

(x)commands

(0-9) debug levels

-n

Don't actually execute the updating actions. This seems to be useful for testing Jamfiles.

Official Release Targets

@release-raw

Builds a pre-release image as a raw image. This can be written directly to disk or used with Qemu

@release-vmware

Builds a pre-release image for use with VMWare. This can also be used with VirtualBox.

@release-cd

A single track ISO CD. `mkisofs` is needed to build this.

@release-anyboot

A custom file that can be burned to CD or written directly to disk or used with Qemu.
It is comprised of an Master Boot Record (MBR), El Torito boot image, and a BFS raw image.
The MBR occupies the first 512 bytes of the El Torito image, which is usually empty.
The BFS image is simply concatenated at the end. Inside the MBR is a partition table entry, which maps to the BFS image.

Non-Release Targets

In addition to looking at DefaultBuildProfiles, there is also a way of finding possible targets by looking at the various "NotFile" statements. A "NotFile" statement is usually used to create a build target with a more user-friendly name. Targets such as these should be viewed as a minimal base.

Some Notes

First of all, any and all files in $(HAIKU_OUTPUT_DIR)–typically /path/haiku/haiku/generated/ will only be accessible to root. To fix this, it is necessary to run chown -R <user>:<group> <path>. Secondly, user errors become much more damaging when sudo jam is used, as you could easily overwrite the wrong partition.

For Linux distributions that make use of udev to maintain /dev, this will only work until you reboot. To allow your user permanent read access to the full disk and write access to the Haiku partition, you need to ask udev to do that for you after every boot. In order to do that, create a udev rule file for local changes (for openSUSE, the file could be named ‘/etc/udev/rules.d/99-local.rules’) and add this to it:

KERNEL==“sda”, MODE=“0664”
KERNEL==“sda2”, OWNER=“your_username”

In order to activate the changes for the current session, please invoke

When building Haiku on a filesystem that is not BFS nor uses a sufficient implementation of xattr, the build system will emulate attributes. An attributes/ folder will be created in your generated folder. It will be necessary to manually remove the emulated attributes folder, ideally before each build cycle. Otherwise some issues may occur.